Clinical studies established the efficacy of monitoring the pregnancies of women with medical complications because of increased fetal mortality. The usefulness of plasma unconjugated estriol has been accepted; however, the short half-life of this steroid in maternal plasma has led to erroneous results. This laboratory has established that a highly significant degree of correlation between maternal plasma unconjugated estriol and 16 alpha hydroxyprogesterone exists in normal pregnancy. There is no correlation between these steroids in diabetics and pregnant women who have intrauterine growth retardation. Studies will be continued on monitoring these women and evaluating the newborn for abnormalities. Basic investigation will focus on the use of porcine ovarian follicles as a model for hormone action of progesterone related to the induction of 16 alpha hydroxylase enzyme.